Recipe Preparation

Heat 1 Tbsp. oil in a large skillet over medium-low. Cook guanciale, tossing often, until browned and crisp, 10–15 minutes. Transfer to a small bowl with a slotted spoon. Pour off all but 2 Tbsp. fat from skillet.

Add ramp bulbs to skillet; season with salt and cook, stirring occasionally, until translucent and tender, about 4 minutes.

Meanwhile, blanch ramp greens in a large pot of boiling salted water until wilted, about 10 seconds. Using a slotted spoon, transfer to a bowl of ice water (save pot of water). Drain, squeeze out excess liquid, and coarsely chop.

Purée ramp greens, ramp bulbs, half of pistachios, and remaining ⅔ cup oil in a food processor until very finely chopped. Add ½ cup Parmesan and process until pesto is almost smooth. Pulse in a little more oil if sauce is too thick; season with salt and pepper.

Mix pesto, ¼ cup pasta water, and butter in a large bowl. Using tongs, transfer pasta to bowl and add guanciale; toss vigorously, adding more cooking liquid as needed until pasta is glossy and well coated with sauce. Taste and add more salt if needed.

Divide pasta among bowls. Top with more Parmesan and remaining pistachios.

Do Ahead: Pesto can be made 2 days ahead. Cover with plastic wrap, pressing directly onto surface, and chill.